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Vulnerability details: VCID-zdxd-83uy-hbad
Vulnerability ID VCID-zdxd-83uy-hbad
Aliases CVE-2020-26890
GHSA-4mp3-385r-v63f
PYSEC-2020-237
Summary denial of service
Status Published
Exploitability 0.5
Weighted Severity 8.0
Risk 4.0
Affected and Fixed Packages Package Details
Weaknesses (3)
CWE-20 Improper Input Validation
CWE-937 OWASP Top Ten 2013 Category A9 - Using Components with Known Vulnerabilities
CWE-1035 OWASP Top Ten 2017 Category A9 - Using Components with Known Vulnerabilities
System Score Found at
epss 0.00572 https://api.first.org/data/v1/epss?cve=CVE-2020-26890
cvssv3.1_qr HIGH https://github.com/advisories/GHSA-4mp3-385r-v63f
cvssv3.1 7.5 https://github.com/matrix-org/synapse
cvssv4 8.7 https://github.com/matrix-org/synapse
generic_textual HIGH https://github.com/matrix-org/synapse
cvssv3.1 7.5 https://github.com/matrix-org/synapse/security/advisories/GHSA-4mp3-385r-v63f
cvssv3.1_qr HIGH https://github.com/matrix-org/synapse/security/advisories/GHSA-4mp3-385r-v63f
cvssv4 8.7 https://github.com/matrix-org/synapse/security/advisories/GHSA-4mp3-385r-v63f
generic_textual HIGH https://github.com/matrix-org/synapse/security/advisories/GHSA-4mp3-385r-v63f
cvssv3.1 7.5 https://github.com/pypa/advisory-database/tree/main/vulns/matrix-synapse/PYSEC-2020-237.yaml
cvssv4 8.7 https://github.com/pypa/advisory-database/tree/main/vulns/matrix-synapse/PYSEC-2020-237.yaml
generic_textual HIGH https://github.com/pypa/advisory-database/tree/main/vulns/matrix-synapse/PYSEC-2020-237.yaml
cvssv3.1 7.5 https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/G7YXMMYQP46PYL664JQUXCA3LPBJU7DQ
cvssv4 8.7 https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/G7YXMMYQP46PYL664JQUXCA3LPBJU7DQ
generic_textual HIGH https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/G7YXMMYQP46PYL664JQUXCA3LPBJU7DQ
cvssv3.1 7.5 https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/U34DPP4ZLOEDUY2ZCWOHQPU5GA5LYNUQ
cvssv4 8.7 https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/U34DPP4ZLOEDUY2ZCWOHQPU5GA5LYNUQ
generic_textual HIGH https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/U34DPP4ZLOEDUY2ZCWOHQPU5GA5LYNUQ
cvssv3.1 7.5 https://nvd.nist.gov/vuln/detail/CVE-2020-26890
cvssv4 8.7 https://nvd.nist.gov/vuln/detail/CVE-2020-26890
generic_textual HIGH https://nvd.nist.gov/vuln/detail/CVE-2020-26890
cvssv3.1 7.5 https://pypi.org/project/matrix-synapse
cvssv4 8.7 https://pypi.org/project/matrix-synapse
generic_textual HIGH https://pypi.org/project/matrix-synapse
archlinux High https://security.archlinux.org/AVG-1296
Reference id Reference type URL
https://api.first.org/data/v1/epss?cve=CVE-2020-26890
https://github.com/matrix-org/synapse
https://github.com/matrix-org/synapse/security/advisories/GHSA-4mp3-385r-v63f
https://github.com/pypa/advisory-database/tree/main/vulns/matrix-synapse/PYSEC-2020-237.yaml
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/G7YXMMYQP46PYL664JQUXCA3LPBJU7DQ
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/G7YXMMYQP46PYL664JQUXCA3LPBJU7DQ/
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/U34DPP4ZLOEDUY2ZCWOHQPU5GA5LYNUQ
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/U34DPP4ZLOEDUY2ZCWOHQPU5GA5LYNUQ/
https://nvd.nist.gov/vuln/detail/CVE-2020-26890
https://pypi.org/project/matrix-synapse
ASA-202011-23 https://security.archlinux.org/ASA-202011-23
AVG-1296 https://security.archlinux.org/AVG-1296
GHSA-4mp3-385r-v63f https://github.com/advisories/GHSA-4mp3-385r-v63f
No exploits are available.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Found at https://github.com/matrix-org/synapse
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none
Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N Found at https://github.com/matrix-org/synapse
Attack Vector (AV) Attack Complexity (AC) Attack Requirements (AT) Privileges Required (PR) User Interaction (UI) Vulnerable System Impact Confidentiality (VC) Vulnerable System Impact Integrity (VI) Vulnerable System Impact Availability (VA) Subsequent System Impact Confidentiality (SC) Subsequent System Impact Integrity (SI) Subsequent System Impact Availability (SA)

network

adjacent

local

physical

low

high

none

present

none

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passive

active

high

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Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Found at https://github.com/matrix-org/synapse/security/advisories/GHSA-4mp3-385r-v63f
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none
Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N Found at https://github.com/matrix-org/synapse/security/advisories/GHSA-4mp3-385r-v63f
Attack Vector (AV) Attack Complexity (AC) Attack Requirements (AT) Privileges Required (PR) User Interaction (UI) Vulnerable System Impact Confidentiality (VC) Vulnerable System Impact Integrity (VI) Vulnerable System Impact Availability (VA) Subsequent System Impact Confidentiality (SC) Subsequent System Impact Integrity (SI) Subsequent System Impact Availability (SA)

network

adjacent

local

physical

low

high

none

present

none

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passive

active

high

low

none

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none
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Found at https://github.com/pypa/advisory-database/tree/main/vulns/matrix-synapse/PYSEC-2020-237.yaml
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none
Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N Found at https://github.com/pypa/advisory-database/tree/main/vulns/matrix-synapse/PYSEC-2020-237.yaml
Attack Vector (AV) Attack Complexity (AC) Attack Requirements (AT) Privileges Required (PR) User Interaction (UI) Vulnerable System Impact Confidentiality (VC) Vulnerable System Impact Integrity (VI) Vulnerable System Impact Availability (VA) Subsequent System Impact Confidentiality (SC) Subsequent System Impact Integrity (SI) Subsequent System Impact Availability (SA)

network

adjacent

local

physical

low

high

none

present

none

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passive

active

high

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none

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Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Found at https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/G7YXMMYQP46PYL664JQUXCA3LPBJU7DQ
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none
Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N Found at https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/G7YXMMYQP46PYL664JQUXCA3LPBJU7DQ
Attack Vector (AV) Attack Complexity (AC) Attack Requirements (AT) Privileges Required (PR) User Interaction (UI) Vulnerable System Impact Confidentiality (VC) Vulnerable System Impact Integrity (VI) Vulnerable System Impact Availability (VA) Subsequent System Impact Confidentiality (SC) Subsequent System Impact Integrity (SI) Subsequent System Impact Availability (SA)

network

adjacent

local

physical

low

high

none

present

none

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passive

active

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none

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Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Found at https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/U34DPP4ZLOEDUY2ZCWOHQPU5GA5LYNUQ
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none
Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N Found at https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/U34DPP4ZLOEDUY2ZCWOHQPU5GA5LYNUQ
Attack Vector (AV) Attack Complexity (AC) Attack Requirements (AT) Privileges Required (PR) User Interaction (UI) Vulnerable System Impact Confidentiality (VC) Vulnerable System Impact Integrity (VI) Vulnerable System Impact Availability (VA) Subsequent System Impact Confidentiality (SC) Subsequent System Impact Integrity (SI) Subsequent System Impact Availability (SA)

network

adjacent

local

physical

low

high

none

present

none

low

high

none

passive

active

high

low

none

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Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Found at https://nvd.nist.gov/vuln/detail/CVE-2020-26890
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none
Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N Found at https://nvd.nist.gov/vuln/detail/CVE-2020-26890
Attack Vector (AV) Attack Complexity (AC) Attack Requirements (AT) Privileges Required (PR) User Interaction (UI) Vulnerable System Impact Confidentiality (VC) Vulnerable System Impact Integrity (VI) Vulnerable System Impact Availability (VA) Subsequent System Impact Confidentiality (SC) Subsequent System Impact Integrity (SI) Subsequent System Impact Availability (SA)

network

adjacent

local

physical

low

high

none

present

none

low

high

none

passive

active

high

low

none

high

low

none

high

low

none

high

low

none

high

low

none

high

low

none
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Found at https://pypi.org/project/matrix-synapse
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none
Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N Found at https://pypi.org/project/matrix-synapse
Attack Vector (AV) Attack Complexity (AC) Attack Requirements (AT) Privileges Required (PR) User Interaction (UI) Vulnerable System Impact Confidentiality (VC) Vulnerable System Impact Integrity (VI) Vulnerable System Impact Availability (VA) Subsequent System Impact Confidentiality (SC) Subsequent System Impact Integrity (SI) Subsequent System Impact Availability (SA)

network

adjacent

local

physical

low

high

none

present

none

low

high

none

passive

active

high

low

none

high

low

none

high

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Exploit Prediction Scoring System (EPSS)
Percentile 0.69005
EPSS Score 0.00572
Published At May 30, 2026, 12:55 p.m.
Date Actor Action Source VulnerableCode Version
2026-05-30T19:37:32.296533+00:00 Arch Linux Importer Import https://security.archlinux.org/AVG-1296 38.6.0